Since the back of the credit card is made of plastic, it won’t absorb ink as easily as a piece of paper would. A felt-tipped pen or a Sharpie pen will leave a permanent signature, and you won’t risk smearing ink across the back of your card. Some people prefer to sign the back of their credit cards with a fine-tip marker.

A credit card sign-up bonus is a financial incentive you receive for opening a new credit card account and using it for a certain amount of spending shortly after account opening.